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									          Maintaining Moisturization
           From Rinse-Off Products
    ISP researchers have developed a novel lipid for rinse-off cleansing
 formulas that not only deposits on the skin but also delivers quantifiable,
                        long-lasting moisturization.

      David J. Moore, Ph.D.                         Steven Orofino                                                      Penny Antonopoulos
       Director, Global R&D                         Senior Manager                                                      Global Personal Care
                                                  Preservatives R&D                                                      Marketing Manager
                                     International Specialty Products, Wayne, NJ

              ECHNOLOGIES ABOUND to         dride that, when combined with                                    texture and appearance are visibly

              ensure that leave-on prod-    palmitic acid, forms a highly ordered                             improved. As Figure 1 shows, the tem-
              ucts deliver moisture to      lamellar gel that is analogous to the                             peratures at which the molecular struc-
              skin. However, ensuring       lipid barrier in healthy skin, and can                            tural transitions of palmitic acid occur
              moisturization through the    duplicate in-vitro the effect of the more                         are similar when combined with casto-
              use of rinse-off cleansing    expensive, complex combination of cho-                            ryl maleate or sphingosine ceramide
              products remains a chal-      lesterol and sphingosine ceramide. Skin                           and cholesterol.
              lenge. Lipids found in
              healthy, moisturized skin
              are typically in a lamellar
gel crystalline state that is responsible                  Fig. 1: Molecular Structural Transitions of Palmitic Acid
for the skin’s barrier function. In the                    The graph shows the intermolecular (chain packing) and intramolecular (chain flu-
stratum corneum, ceramides and cho-                        idity) phase transition temperatures of palmitic acid in combination with castoryl
lesterol organize together with fatty                      maleate and in a widely used skin barrier model with ceramide and cholesterol.
acids to form the highly ordered lipid                     Castoryl maleate, functioning as a skin lipid analog, maintains a fatty-chain fluid-
phase of the skin.                                         ity and crystalline (orthorhombic) packing very similar to those maintained by the
   Rinse-off personal cleansing prod-                      ceramide/cholesterol model.
ucts designed to remove dirt and debris
from the skin can also remove protec-
tive lipids, which can weaken the skin’s                         50
natural defensive barrier and result in                          45
dry, flaky skin. Even emollient-rich
cleansers can leave the skin feeling and
                                              Temperature (°C)

looking dry, since most emollients are                           35
washed away when the cleanser is                                 30
rinsed off.
   A patented lipid analog from
International Specialty Products (ISP)                           20
(INCI: castoryl maleate) has been                                15
demonstrated by ISP not only to deposit
onto the skin from rinse-off cleansing
formulas, but also to deliver quantifi-                          5
able, long-lasting moisturization.                               0
   Castoryl maleate (Ceraphyl RMT) is                                       Maleated Castor Oil                                Skin Lipid Model
an ISP-patented molecule made by the
reaction of castor oil with maleic anhy-                                      I Fatty Acid Chain Packing Tm     I Fatty Acid Chain Fluidity Tm

                                                                                                  HAPPI • November 2006 • www.Happi.com           77
Demonstrating Deposition                                                    ly attenuated total reflectance Fourier-                     strate deposition of a body wash con-
Figure 2 shows the results of an                                            Transform IR (HATR-FTIR) spec-                               taining the lipid analog castoryl
advanced in-vivo technique, horizontal-                                     troscopy, which was used to demon-                           maleate onto the skin. First, the spec-
                                                                                                                                         trum of untreated skin was obtained
                                                                                                                                         (Line B). Then, the skin was cleansed
                                                                                                                                         with a prototype containing the castoryl
          Fig. 2: Good Deposition of Castoryl Maleate                                                                                    maleate. After rinsing, the HATR-FTIR
          Determining deposition onto skin via in-vivo HATR-FTIR technique demonstrates the                                              spectrum of the cleansed skin was
          deposition power of body wash containing castoryl maleate. Line A: Skin after                                                  recorded (Line A).
          cleansing with body wash containing castoryl maleate. Line B: Baseline spectrum of                                                 The spectrum of the deposited mate-
          skin. Line C: Mathematical difference between Lines A and B. Line D: Spectrum of                                               rial (Line C), which is derived by sub-
          body wash containing castoryl maleate.                                                                                         tracting one spectrum (Line B) from the
                                                                                                                                         other (Line A), was found to be essen-
                                                                                                                                         tially identical to a reference spectrum
                                                                                                                                         of the body wash itself (Line D). Further
                                                                                                                                         analysis of the spectra showed that a
                                                                                                                                         significant amount of added material
                          Line A                                                                                                         remained on the skin after rinsing.
                                                                                                                                             In-vivo tests have also confirmed the
                                                                                                                                         beneficial effect of cleansing with prod-
                          Line B                                                                                                         ucts containing castoryl maleate. Using
                                                                                                                                         quantitative skin hydration tests, proto-
                                                                                                                                         type rinse-off products containing the
                                                                                                                                         lipid analogue were compared to skin
                          Line C                                                                                                         cleansed with soap.
                                                                                                                                             Results have shown significant
                                                                                                                                         improvement in skin hydration after
                          Line D
                                                                                                                                         five days of treatment with prototypes
                               2700          2800        2900       3000           1400         1500    1600        1700   1800   1900
                                                                                                                                         containing castoryl maleate. The skin’s
                                                                                                                                         texture and condition were clearly
                                                                                                                                         improved and remained so even after
                                                                           Wave number (cm-1)
                                                                                                                                         usage, during a three-day regression
                                                                                                                                         period. Long-term moisturization is typ-
                                                                                                                                         ically delivered only by leave-on mois-
                                                                                                                                         turizing products.
               Fig. 3A: Significant and Long-lasting Moisturization
               There is significant moisturization of body wash containing 2.5% castoryl maleate
                                                                                                                                         Benefits of Castoryl Maleate
               over a five-day treatment period and a three-day regression period in comparison to
                                                                                                                                         Clinical studies were performed evalu-
               the no-treatment and water-treatment controls.
                                                                                                                                         ating two carefully constructed formu-
                                                                                                                                         lations to demonstrate the ability of cas-
                     80                                                                                                                  toryl maleate to deliver moisturization
                     75                                                                                                                  benefits via rinse-off cleansing prod-
                     60                                                                                                                     Panelists’ arms were used in these
  Temperature (°C)

                     55                                                                                                                  studies. The panelists’ arms were
                     50                                                                                                                  washed for one week with alkaline
                                                                                                                                         soap. After one week of washing, base-
                     35                                                                                                                  line measurements were taken on the
                     30                                                                                                                  marked test sites. A clinician then
                     25                                                                                                                  applied a measured dose of the test
                                                                                                                                         material, washed the marked area and
                     10                                                                                                                  then uniformly rinsed and dried the
                      5                                                                                                                  area. This treatment protocol was con-
                      0                                                                                                                  ducted once a day for five days.
                                                Day 5                                           Day 3: Regression                        Measurements were taken after the
                                                                                                                                         five days of treatment. At the end of five
                                   I No Treatment I Water wash I 2.5% Cast. Mal. Body Wash I PL 141 Moisturizer                          days, the treatment ceased. Regression
                                                                                                                                         measurements were taken on the third

78                   HAPPI • November 2006 • www.Happi.com
day following two days of no treatment.                      The first evaluation would deter-                   created within the cleansing formula-
Skin hydration measurements were                          mine whether moisturization from a                     tion. Using castoryl maleate, a separate
taken using the Skicon 200 skin surface                   formula containing castoryl maleate                    lamellar gel phase can be developed
hygrometer. Visual assessment was                         with a structured lipid phase could be                 within most mild surfactant cleansing
made using the Scopeman MS-503                            delivered from a body wash. Formula 1                  systems. The resulting lamellar gel,
Video Microscope at the 75x level.                        (#10510-99-1) was created using 2.5% of                similar to the native lipids of the skin,
Images were captured at baseline, after                   castoryl maleate. Here, castoryl                       acts as both the deposition vehicle and
five days of treatment, and after three                   maleate is combined with fatty acids to                the moisturizer system.
days of regression.                                       create a lamellar gel in situ, which is                    This formula was compared to a pos-
                                                                                                                 itive control, a leave-on moisturizer con-
                                                                                                                 taining a lamellar lipid gel system
  Fig. 3b: Moisturizing Body Wash with 2.5% Castoryl Maleate                                                     {ProLipid 141 [INCI: Glyceryl stearate
                                (Formula #10510-99-1)                                                            (and) behenyl alcohol (and) palmitic
  Scopeman photos of skin surface taken at 75x magnification during in-vivo skin hydra-                          acid (and) stearic acid (and) lecithin
  tion tests clearly show the marked improvement in skin texture and condition after                             (and) lauryl alcohol (and) myristyl alco-
  five days of cleansing with castoryl maleate body wash and a three-day regression                              hol (and) cetyl alcohol]}, and two nega-
  period.                                                                                                        tive controls, a water wash and no treat-
                                                                                                                     Figure 3a graphically illustrates the
                                                                                                                 results of skin conductance measure-
                                                                                                                 ments obtained from the clinical testing
                                                                                                                 of Formula 1. As the results demon-
                                                                                                                 strate, skin hydration with the 2.5%
                                                                                                                 castoryl maleate moisturizing body
                                                                                                                 wash was excellent after five days of
                                                                                                                 treatment; in addition, skin moisturiza-
                                                                                                                 tion persisted through three days of
                                                                                                                 regression. The Scopeman photos taken
                                                                                                                 during the hydration tests clearly show
                                                                                                                 significant improvement in skin texture
                                                                                                                 and condition (Fig. 3b).
                                                                                                                     The second clinical study evaluated
                                                                                                                 Formula 2 (#10648-111-1), which illus-
                                                                                                                 trates a different formulation approach,
           Day 0                                   Day 5                             Regression
                                                                                                                 the creation of a cleansing system that
                                                                                                                 truly moisturizes. In this clear moistur-
                                                                                                                 izing shower gel, 0.55% castoryl
 Fig. 4a: Clear Moisturizing Shower Gel with 0.55% Castoryl Maleate                                              maleate was incorporated into the for-
                                 (Formula #10648-111-1)                                                          mula. In order to maintain clarity, such
 Superior long-term moisturization benefits of clear bath gel using 0.55% castoryl                               a low level of castoryl maleate needed to
 maleate are graphically demonstrated in comparison to a water wash control.                                     be used in addition to the removal of
      65                                                                                                         any fatty acids. Of equal importance, a
      60                                                                                                         much higher ratio of amphoteric to
      55                                                                                                         anionic surfactant was employed.
      50                                                                                                             Since this formulation lacks the
      45                                                                                                         fatty acids and lipids necessary for in-
                                                                                                                 situ formation of liquid crystalline
                                                                                                                 lamellar gel phases in the product, it is
                                                                                                                 likely that the castoryl maleate is
                                                                                                                 deposited onto the skin, where it could
      15                                                                                                         incorporate into the skin’s own lipids. It
      10                                                                                                         may also increase the delivery and
       5                                                                                                         retention of glycerol from the body wash
       0                                                                                                         and thereby improve skin hydration.
                   Day 1 (Dry Scores)                       Day 5                     Day 3: Regression              This second formula was compared
                                                                                                                 to a similar clear rinse-off system with-
                             I w/ Cast. Mal   I w/o Cast. Mal.   I Water Washed   I Untreated
                                                                                                                 out the inclusion of castoryl maleate.
                                                                                                                 The other two treatment sites were

                                                                                                          HAPPI • November 2006 • www.Happi.com        79
Fig. 4b: Clear Moisturizing Shower Gel with 0.55% Castoryl Maleate                       Combine Phase A, mixing well between
                             (Formula #10648-111-1)                                      additions. Heat Phase A to 70-75°C.
Long-term moisturization benefits of clear bath gel using 0.55% castoryl maleate         Combine Phase B and heat to 70-75°C
are visually captured via magnified Scopeman photos of skin surface taken during         while mixing. Add Phase B to Phase A,
clinical testing.                                                                        continue mixing, cool to 40-45°C, and
                                                                                         add Phase C.
              w/ Cast. Mal.     w/o Cast. Mal.     Water Wash         Untreated
                                                                                         pH=7.02;     Viscosity=20,000    cps
                                                                                         (Brookfield Model RVT, TB @ 5 RPM)
     Day 0
                                                                                          Clear Moisturizing Shower Gel
                                                                                              with Castoryl Maleate
     Day 5                                                                               Ingredients:                    %Wt.
                                                                                         Phase A
                                                                                         Mirataine CB (Rhodia)           20.00
                                                                                            (Cocamidopropyl betaine)
                                                                                         Ceraphyl RMT (ISP)               0.55
     Regr.                                                                                  (Castoryl maleate)
                                                                                         Versene NA (Dow Chemical)        0.10
                                                                                            (Disodium EDTA)
                                                                                         Glycerin                          6.00
                                                                                         Phase B
exposed to a water wash and no treat-        Standapol ES-3 (Cognis)             30.00   Deionized water                 34.35
ment. As Figure 4a graphically illus-           (Sodium laureth sulfate)                 Standapol ES-3 (Cognis)         20.00
trates, skin conductance tests compar-       Tego Betaine F (Degussa)            15.00      (Sodium laureth sulfate)
ing clear body wash formulations with           (Cocamidopropyl betaine)                 Phase C
and without 0.55% castoryl maleate           Softigen 767 (Sasol)                 6.00   Germaben II-E (ISP)              1.00
demonstrate the superior long-term              (PEG-6 caprylic/capric glyceride)           [Propylene glycol (and)
moisturization benefits to be gained         Glycerin                             3.00      diazolidinyl urea (and)
with even less than 1.0% castoryl            Citric acid (H&R))                   0.10      methylparaben       (and)   propyl-
maleate as part of the formulation.          Titanium Dioxide 3328                0.50   paraben]
These benefits can clearly be seen in the       (Whittaker, Clark & Daniels)             Phase D
Scopeman photos taken of the skin sur-       Triethanolamine, 99%                 1.80   Deionized water                 15.00
face during clinical testing (Figure 4b).       (Crompton Corp.)                         Sodium chloride                  3.00
    Other formulations using castoryl        Plantaren PS200 (Cognis)            13.50
maleate have been developed: a gentle           [Lauryl glucoside (and)                  Procedure:
moisturizing facial cleanser (Formula 3,        sodium laureth sulfate]                  Combine Phase A, mixing well between
#10888-145-1) and an in-shower skin          Gafquat 755N (ISP)                   1.50   additions. Heat Phase A to 45-50°C.
moisturizer (Formula 4, #11089-74-1).           (Polyquaternium-11)                      Combine Phase B and heat to 45-50°C
    As the results from the clinical stud-   Versene NA (Dow Chemical)            0.10   while mixing. Add Phase B to Phase A,
ies demonstrate, formulators develop-           (Disodium EDTA)                          continue mixing, cool to 40°C, and add
ing rinse-off cleansing products with        Phase B                                     Phase C. Combine Phase D, add slowly
moisturization benefits will find casto-     Prifac 7971 (Uniqema)                4.50   at 35-40°C.
ryl maleate an excellent ingredient for         (Distilled palm fatty acid)
its ability not only to enhance skin-bar-    Ceraphyl RMT (ISP)                   2.50   pH = 5.30; Viscosity = 11,400 cps
rier repair in rinse-off applications but       (Castoryl maleate)                       (Brookfield Model RVT, TA @ 10 RPM)
also to provide skin conditioning and        Soybean oil                          4.00
long-term moisturization.                    Ceraphyl 41 (ISP)                    4.50         Gentle Facial Cleanser
                                                (C12-15 alkyl lactate)                         with Castoryl Maleate
     Moisturizing Body Wash                  Phase C                                                 (#10888-145-1)
     with Castoryl Maleate                   Fragrance #4019-10156 (Belmay) 0.75         Ingredients                     %Wt.
            (#10510-99-1)                    Germaben II (ISP)                    1.00   Phase A:
Ingredients:                       % Wt.        [Propylene glycol (and) diazoli-         Deionized water                 65.10
Phase A                                         dinyl urea (and) methylpara-             Versene NA (Dow Chemical)        0.15
Deionized water                     11.25       ben (and) propylparaben]                    (Disodium EDTA)

80    HAPPI • November 2006 • www.Happi.com
Plantaren 2000N (Cognis)             18.00      (Magnesium aluminum silicate)             lidinyl urea (and) iodo-
   (Decyl glucoside)                         Glycerin                          2.50       propynyl butylcarbamate]
Mackam 2C75 (McIntyre)                8.00   Dry Flo PC (National Starch)      0.75    J’adore VV19-00054 (Ungerer)       0.15
   (Disodium cocoamphodi-                       (Aluminum starch octenylsuccinate)        (Fragrance)
   acetate)                                  Phase B
Crothix (Croda)                       2.25   Carnation Light (Ruger)           5.00    Procedure:
   (PEG-150 penta-                              (Mineral Oil)                          In a proper size vessel, combine water,
   erytryl tetrastearate)                    Petrolatum Snow (Penreco)         2.50    glycerin and EDTA with mixing. Next,
Phase B                                         (Petrolatum)                           sprinkle in Veegum Ultra. Third, sprin-
Ceraphyl RMT (ISP)                    2.00   ProLipid161 (ISP)                 4.00    kle in Dry Flo PC with good mixing and
   (Castoryl maleate)                           [Behenyl alcohol (and)                 begin to heat to 70-75ºC. In a separate
Liquid Germall Plus (ISP)             0.75      cetearyl alcohol (and)                 vessel, combine all ingredients in Phase
   [Propylene glycol (and) diazol-              hydroxyethyl cetearamidopropyl         B with good mixing; heat to 70ºC. When
   idynyl urea (and) iodo-                      dimonium chloride]                     both phases are at 70-75°C, add Phase
   propynyl butylcarbamate]                  Ceraphyl RMT (ISP)                2.50    B to Phase A with good mixing. When
Phase C                                         (Castoryl maleate)                     the batch is uniform, begin the cooling
Fragrance (FFS)                       0.15   Lanette 18 Deo NF (Cognis)        0.75    process. At 30°C, add Phase C ingredi-
   (Cool Water type)                            (Stearyl alcohol)                      ents in order listed. Mix well between
Solubilizer 2/014160 (Dragoco)        0.15   Lanette 16 NF (Cognis)            0.75    additions. QS for water loss and mix to
   [PEG-40 hydrogenated castor                  (Cetyl alcohol)                        room temperature.
   oil (and) trideceth-9 (and)               Phase C
   propylene glycol]                         Liquid Germall Plus (ISP)         0.60    pH = 5.30; Viscosity = 29,000 cps
Phase D                                         [Propylene glycol (and) diazo-         (Brookfield Model RVT, TB @ 5 RPM) G
Glycerin                              3.00
Yellow 5 (LCW)                        0.25
   (FD&C Yellow No. 5, 0.1%
   aqueous solution)
Red 40 (LCW)                          0.20
   (FD&C Red No. 40, 0.1%
   aqueous solution)

In a vessel, combine ingredients in
Phase A in order listed; mix slowly after
each addition. Begin heating Phase A to
60-70°C; mix until each ingredient is
fully dissolved. Begin cooling down the
batch. At 30-35°C, add castoryl maleate
very slowly in small portions and stir
slowly until fully incorporated and clear
(avoid entrapping air). Allow enough
time for stirring (approx. 10-20 min-
utes). Carefully add Liquid Germall
Plus to the main batch and mix.
Separately premix Phase C ingredients
at room temperature, add premix to the
main batch and mix slowly. At 25-30°C,
add Phase D ingredients and mix well.
pH = 6.29; Viscosity = 4,000 cps
(Brookfield Model RVT, TB @ 5 RPM)

   In-Shower Skin Moisturizer
Ingredients                          %Wt.
Phase A
Deionized water                      79.90
Disodium EDTA (Dow Chemical)          0.10
Veegum Ultra (RT Vanderbilt)          0.50

                                                                             HAPPI •   November 2006 • www.Happi.com       81

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